1. Technical Field
The invention relates to methods and materials involved in producing organic compounds such as organic acids.
2. Background Information
Ascorbic acid (vitamin C) has many important nutritional uses. In fact, ascorbic acid is an essential nutrient to humans, and must be obtained from diet to prevent vitamin C deficiencies such as scurvy. In addition, some medical practitioners claim that ascorbic acid has the potential to prevent and treat the common cold, flu, and cancer. Thus, diet supplements containing ascorbic acid are widely used.
Ascorbic acid also has many important industrial uses. For example, ascorbic acid can be used in meat processing, nutritional supplements, and animal foods. In fact, several industrial manufactures can produce 10,000 metric tons annually of ascorbic acid and related ascorbic acid compounds such as calcium ascorbate and sodium ascorbate.
The “Reichstein” method is a commonly used method for producing ascorbic acid from D-glucose or a D-glucose precursor such as corn syrup. This method involves six discrete chemical steps as well as a fermentation step. For example, one of the chemical steps involves converting 2-keto-L-gulonic acid into ascorbic acid by treating the 2-keto-L-gulonic acid with acid at a temperature greater than 60° C.
Several other manufacturing processes containing at least one chemical step are also used to produce ascorbic acid. Specifically, ascorbic acid has been produced using methods that chemically convert D-glucose into L-sorbitol prior to a fermentation step, methods that chemically convert 2-keto-L-gulonic acid into ascorbic acid after a fermentation step, and methods that chemically convert D-glucose into L-sorbitol prior to a fermentation step in addition to chemically converting 2-keto-L-gulonic acid into ascorbic acid after a fermentation step.